The present invention relates to a method and apparatus for testing and repairing a conduit. In particular, it relates to an inflatable packer operable for placing in a subsurface conduit, and for testing and repairing joints in the conduit.
In subsurface conduits, such as sewer lines, it is frequently necessary to repair leaking joints of the conduit. Packer assemblies have been known which may be used for isolating a leaking joint and for injecting a hardenable grouting material into the joint. These leaking joints are most advantageously located by the use of a television camera placed in the conduit with the packer. The television camera is used to visually locate leaks and to center the packer over the faulty joint such that the leak may be isolated and subsequently repaired with the grouting material.
This method is successful where the leaking joint may be easily determined by invading ground water or by an obvious defect in the joint. However, when a bad joint cannot be detected visually, it is desirable to pressure test each joint in the sewer line to locate those which are defective. The ability to pressure test each joint eliminates the necessity of grouting each joint to be sure that all leaking joints have been repaired.
Inflatable packers for pressure testing joints are known which may be placed over a joint to be tested and inflated to thereby isolate the joint. Air is then introduced into the isolated area and pressurized to a desired pressure. The air pressure in the isolated area is then monitored to determine if the air is dissipating through the joint thus indicating a leak.
It is also desirable to provide in the packer means for determining the hydrostatic pressure of ground water invading a subsurface conduit to determine the pressure needed to displace grouting material against this hydrostatic pressure to the joint to be repaired. It is also desirable to be able to pressure check the repaired joint to ensure that the grouting repair is successful and that the repaired joint will hold pressure.
Prior art packers have been constructed which include an electronic pressure sensor for determining the pressure in the isolated joint area. An electrical signal is then placed on an electrical conduit which leads from the packer to the surface. Such packers are expensive in that an electronic telemetering system is needed to transmit the electrical pressure signal to the surface and additional electronic equipment is needed to receive the electrical signal and convert it to a readable recording which may be monitored by the packer operator. The placing of electronic equipment in the packer is also undesirable because of the environment of the sewer line.
The packer of the present invention includes an inflatable means for isolating a portion of the conduit to be tested. Additionally, means are provided for applying fluid pressure to the isolated conduit portion.
The packer includes a fluid filled pressure responsive element adjacent the isolated conduit portion which transmits fluid pressure to one end of the packer through a fluid conductor located in the packer. A pressure indicating means is connected to the fluid conductor and is located such that the pressure indication may be viewed by the associated television camera. It can thus be seen that a greatly simplified packer results which indicates in the conduit the pressure in the isolated portion of the conduit. This pressure indication is viewed by a television camera which transmits the pressure indication to the surface with the picture of the conduit being inspected and repaired. This arrangement minimizes the number of electrical connections and electronic components necessary to monitor from the surface the desired pressure readings.
Since the fluid filled pressure responsive element is always subjected to fluid pressure in the isolated conduit portion, the packer of the present invention may be used to conduct pressure tests of conduit joints, measure hydrostatic pressure of invading ground water, and conduct pressure tests of the repaired joint.